#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
int main() {
    char ch;
    int hash[128] = { 0 };
    int count = 0;
    while ((ch = getchar()) != '\n') {
        hash[(int)ch]++;
    }
    for (int i = 0; i < 128; i++) {
        if (hash[i]) {
            count++;
        }
    }
    printf("%d", count);
    return 0;
}